Gear-tooth calipers.



Patented Feb. 6,1900.

J. BUULET.

GEAR TOOTH CALIPERS.

(Application filed Oct, 30, 1899.)

INVENTEIFQ (No Model.)

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SPECIFICATION forming part of Letters Patent No. 643,080, dated February 1900- Application filed October 30, 1899. Serial No. 735,166. (No model.)

To all whom it may concern.-

Be it known that I, JOSEPH BoULET, a citizen of Canada, residing at Beverly, in the county of Essex and State of Massachusetts, have invented a new and useful Improvement in Gear-Tooth Calipers, of which the follow ing is a specification.

My invention relates to improvements in micrometer-calipers specially adapted to the measurement of gear-teeth,the object of which is to provide means for conveniently and accurately measuring such teeth on the pitchline and at the same time correctly locating the measuring-points on such line, thereby detecting very minute variations from the true form of the teeth which may occur from imperfect cutters or cutting operations. I at tain said object by the mechanism illustrated in the accompanying drawings, in which- Figure 1 is an elevation of my improved calipers and includes also an illustrative section of a gear introduced to show the manner of applying the measuring-tool or calipers to the teeth when in practical use. Fig. 2 is an under side view of the calipers. Fig. 3 is a central longitudinal section taken horizontally through Fig. -1. Fig. 4 is a cross-section taken as on line a: .50, Fig. 1. Fig. 5 is a cross-sectiontaken as on line a a, Fig. 1, and viewed from the right of said line. Fig. 6 is an enlarged sectional View showing the construction of the spindle-bearing, which is also shown in Fig. 3.

The calipers as illustrated in said drawings comprises a micrometer composed of telescopic shells A and B, arranged to slide one upon the other in a well-known manner and marked with indicating-scales in the usual Way; a central spindle O, which extends through the outer end of shell A and is clamped thereto by means of a shoulder and nut on the spindle, as shown in Fig. 3, the spindle being also threaded into shell B and having a bearing in a projection which supports its opposite end; a bar D,which is firmly attached to the outer end of shell B, being fitted and properly secured in a groove in the head B, formed upon and as an integral part of said outer end of shell B, as shown in Figs. 1,2,and 8, and through which spindle 0 passes, as shown in Fig. 3; a slide or carriage E, mounted upon said bar and provided with a locking-screw E; a movable jaw F, attached to slide E, and a cooperating fixed jaw F, secured to the outer end of bar D. There is also mounted upon bar D, between the jaws The novelty which constitutes my invention consists in the combination of the two micrometers with adjustable measuring-points under the peculiar construction and mode of operation which I will now describe, and point out in the appended claims.

A projection J (see Fig. 5) extends outward from the face of slide E and carries a threaded bushing K, which is screwed into said projection and serves as a bearing for the end of spindle O, as shown in Figs. 3 and 6. A shoulder O on the spindle bears against the enlarged end of saidbushing,which serves as a journalbearing for the projecting end of the spindle. Into this end is screwed an extension-spindle 0 up to a shoulder O thereon, which bears against spindle C opposite shoulder O. The extension-spindle 0 thus secured in the end of spindle 0 serves as a practical continuation of the latter, but the screw-threads out thereon are but one-half the pitch of the threads on the main spindle C and are threaded into a projection M on the sliding block which carries the locating-gage I. By this construction when spindle O is turned to move slide E in either direction a differential movement is produced, and the locating-gage I will be moved by the spindle only half the distance that slide E, with its jaw F, is moved thereby, and therefore to whatever distance apart jaws F and' F may be thus adjusted the 10- eating-gage I will always be moved by spindle C to a position exactly midway between the jaws. The projection J, being divided at its outer end, a screw L is threaded through the parts thereof and serves as the means by which the bushing K may be secured against turning in its place by thereby pinching the divided branches of the projection together upon the bushing.

In Fig. 1 the calipers is illustrated as when in practical use on a gear-tooth P, the locating-gage I being properly adjusted by its inicrometer to bear upon the top of the tooth, as shown, and in such relation to the measuring-points of the cooperating jaws F and F as to locate them accurately on the pitchline P of the tooth the thickness of which is to be measured by them. Thus when the calipers is adjusted to give the correct dimensions required any variation therefrom arising from the use of an imperfect cutter or otherwise may be readily detected and measured even to one-thousandth of an inch.

The locating-gage is micrometrically adjustable longitudinally relatively to the tooth to be measured and independently of the adjustment of the jaws relatively to each other, while by a separate micrometer the jaws are adjustable in relation to each other and the locating-gage is at the same time and by the same means adjustable in its central position between the jaws whatever their distance apart may be.

1. Acaliper, embodying the combination of a supporting frame or bar; a micrometer attached to the bar; a jaw the movements whereof upon the bar are regulated and measured by said micrometer attachment; a cooperating jaw immovably attached to the bar; a lo eating-gage mounted upon the bar midway between the jaws and extending at right angles to, and movable laterally upon, the bar; and a micrometer attachment to the locatinggage for regulating and measuring its longitudinal movements; all substantially as set forth.

2. Acaliperembodying the combination of a pair of jaws, one fixed and the other movable; means for micrometrically adjusting and measuring the movement of the movable jaw; a locating-gage midway between the jaws adjustable at right angles to the movement of the jaw, and also movable in the same direction therewith; means for micrometrically efiecting such adjustment of the gage; and means for simultaneously moving the gage with the jaw and in the same direction, but differentially so as to maintain it in a constant central position between the jaws; all substantially as and for thepurposes specified.

3. In combination, bar D; jaws F and F, thereon, one fixed and the other movable; 1oeating-gage I, placed centrally between the jaws upon the bar, and being adjustable at right angles to, and arranged to also slide upon, the bar; the threaded spindle C, 0 constructed and arranged to impart differential movements to jaw F, and gage I, upon the bar, simultaneously and in the same direction; and micrometer devices for measuring and indicating the movements of the jaw and gage; all substantially as specified.

JOSEPH BOULE'P.

Witnesses:

EUGENE HUMPHREY, PETER A. COUPAL. 

